The present disclosure relates generally to differential signaling, and more particularly, to digital differential line drivers.
Differential signaling is a method of transmitting information electrically with two complementary signals sent on two paired wires, referred to as a differential pair. Differential signaling may be used for both analog and digital applications. Additionally, differential pairs may be used in different devices, such as in printed circuit boards, cables (e.g., twisted pair or ribbon cables), or connectors, among others. Differential signals may be used to convey or communicate information from one subsystem to another subsystem, for example, using a transmitter (driver) and receiver configuration operating in a differential manner. For example, at receiver side, the receiving device determines the difference between the two signals and because the receiver ignores the voltages of the wires with respect to ground, small changes in ground potential between the transmitter and receiver do not affect the ability of the receiver to detect the signal.
Differential signals may be used in wireless communication systems. For example, differential signaling may be used in satellite communications between a command receiver on the ground and electronics on a spacecraft, such using central telemetry and command units (CTCUs).
In the electronics industry, such as the portable and mobile devices technology, there is also continuing trend to lower supply voltages in order to save power and reduce unwanted emitted radiation. A low supply voltage, however, causes problems with signaling because the supply voltage reduces noise immunity of the system. Differential signaling helps to reduce these problems because, for a given supply voltage, differential signaling provides twice the noise immunity of a single-ended system. However, differential signaling may also be used in higher voltage systems (e.g., 5 volts or more) having long cable lengths many times that of single-ended systems.
However, with conventional differential driver arrangements, it is difficult (with complex controls), if not impossible, to determine whether a component has failed. Accordingly, in these conventional systems, a component failure is propagated to other parts of the systems, such as from one subsystem to another subsystem, thereby affecting the reliability of the overall system.